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authorDan Williams <dan.j.williams@intel.com>2009-12-17 21:52:39 +0100
committerDan Williams <dan.j.williams@intel.com>2009-12-17 21:52:39 +0100
commitcd78809f6191485a90ea6c92c2b58900ab5c156f (patch)
treed17a0e30178ec8ae78e04df69ca3d7b280054361 /drivers/dma
parentLinux 2.6.32 (diff)
downloadlinux-cd78809f6191485a90ea6c92c2b58900ab5c156f.tar.xz
linux-cd78809f6191485a90ea6c92c2b58900ab5c156f.zip
ioat3: fix p-disabled q-continuation
When continuing a pq calculation the driver needs 3 extra sources. The driver can perform a 3 source calculation with a single descriptor, but needs an extended descriptor to process up to 8 sources in one operation. However, in the p-disabled case only one extra source is needed. When continuing a p-disabled operation there are occasions (i.e. 0 < src_cnt % 8 < 3) where the tail operation does not need an extended descriptor. Properly account for this fact otherwise invalid 'dmacount' values will be written to hardware usually causing the channel to halt with 'invalid descriptor' errors. Cc: <stable@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/ioat/dma_v3.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index 42f6f10fb0cc..e58ecb29513f 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -650,9 +650,11 @@ __ioat3_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
num_descs = ioat2_xferlen_to_descs(ioat, len);
/* we need 2x the number of descriptors to cover greater than 3
- * sources
+ * sources (we need 1 extra source in the q-only continuation
+ * case and 3 extra sources in the p+q continuation case.
*/
- if (src_cnt > 3 || flags & DMA_PREP_CONTINUE) {
+ if (src_cnt + dmaf_p_disabled_continue(flags) > 3 ||
+ (dmaf_continue(flags) && !dmaf_p_disabled_continue(flags))) {
with_ext = 1;
num_descs *= 2;
} else